Conformable Single-Walled Carbon Nanotube Thin Film Strain Sensors for Structural Monitoring

The need for monitoring the condition of large-scale infrastructure systems has motivated a recent interest in novel sensor technologies for structural health monitoring. To provide the structural health monitoring system with data that captures local structural behavior, the measurement of component-level strain is valuable. Although current foil-based strain gauges are capable of measuring strain deformations, their low sensitivity and drift properties render them poorly suited for long-term field installation. In this study, a novel strain sensor is presented for the purpose of structural monitoring. The presented strain sensor is based on a layer-bylayer chemical film deposition technique to produce a nanocomposite consisting of single-walled carbon nanotubes (SWNT) and polyelectrolytes (PE). Engineered at the molecular-level, the performance of the thin film strain sensor can be optimized for structural monitoring applications, including attainment of high gauge factors. To validate the sensitivity and precision of the conformable SWNT-PE thin film strain sensor, this study undertakes a series of laboratory experiments where thin films are loaded under monotonic and cyclic load patterns.